Electrical resistor



p'r/a M. E. BOURNS ELECTRICAL RESISTOR Sept. 13, 1960 2,952,825

Original Filed July 5, 1955 1% i III-"Ill I m: "II-6% INVENTOR.

MAPLAA/ 1 BOU'P/VS ATTORNEYS.

United States Patent '0 ELECTRICAL RESISTOR MarlanE. Bourns, 2482' Carlton Place, Riverside, Calif.

Continuation of abandoned application Ser. No. 519,847, July 5,1955. This application Sept. 14, 1959, Ser. No. 839,978.

1 Claim. (Cl. 338-150) The present invention relates to new and improved electrical components and is a continuation of my now abandoned application, Serial No. 519,847, filed July 5, 1955, entitled Electrical Resistor (as amended by Examiner). More specifically, it relates to new and improved electrical potentiometers and like devices.

A great many organizations at the present time are devoting considerable time and money to: the development of various electrical or electronic devices which consist'primarily of a number of separate electrical components secured together in a compact assembly capable of being used as an integral unit in a large device, such as for example, a computer or the like. One particular effort along these lines has been financed to a large extent by the United States Air Force and is commonly termed Project Tinker Toy. In this Tinker Toy Project, the electrical components utilized are in the form of small fiat squares approximately /1 of an inch in length along each edge and of varying thickness. Each of the components in thistype of a structure is secured within an elongated cage consisting of 12 Wires, three of which are disposed along each edge of each component. All of the wires used are located parallel to one another. At times, less than twelve wires are employed, and discontinuous wiresare employed in order to make or complete a desired electrical circuit.

As nearly as is known at the present time, no potentiometers or like electrical components of essentially an adjustable nature have been developed which are capable of being used satisfactorily in the so-called Tinker Toy Project. It is a broad object of this invention to provide adjustable potentiometers and resistors which can be satisfactorily utilized in the so-called Tinker Toy type of construction. Another object of the instant invention is' to provide adjustable electrical components of the class described which are capable of Wide use in other diverse applications and 'Which may be easily manufactured with a minimum of difliculty. A further object of this invention is to provide small electrical components of the category indicated which are rugged so that they are capable of standing a large amount of abuse. Another object ofthis disclosure is-to teach the manufacture and construction of potentiometers and the like which may be directly secured to various wires in an electrical circuit, andwhich may be supported in a desired position by these wires.

Further objects of this disclosure as well as many other advantages of the constructions describedherein will be apparent'from the remainder of this description, including 2,952,825 Patented Sept. 13, 1960 the appended claims and the accompanying drawings, in which:

Fig. 1 is an isometric view of a potentiometer of the present invention;

Fig. 2 is across sectional view taken at line 2-2 of Fig. 1;

Fig. 3 is across sectional view taken at line 3-3 of Fig. 1;

Fig. 4 is an'isometric view of a member utilized in the potentiometer shown in Fig. 1;

Fig. .5 is a view similar to Fig. 3 of a modified potentiometer of the invention;

Fig. 6 is. a cross sectional view taken at line 66 of Fig. 5;

Fig. 7 is a side view of a second modified potentiometer ofthe invention;

Fig. 8 is across sectional view taken at line 8-8 of Fig. 7; and

Fig. 9 is a cross sectional view taken at line 99 of Fig. 8.

It is to be understood that the accompanying drawings are not scaled to any precise commercial unit but are designed merely to illustrate the essential, preferred features of the present invention. Wherever convenient for purposes of illustration and explanation, like numerals have been utilized to designate like parts.

The present invention is defined in detail by the appended claims forrning a part of the specification. If desired, however, the present invention may be briefiy summarized as required by the Rules of Practice of the United States Patent Ofiice as being primarily concerned with new and improved electrical instruments or components which include: a housing; means defining a disc shaped cavity within said housing; first and secondelectrical means disposed within said cavity; a movable member located within said cavity; means for rotating said movable member within said cavity, said means projecting to the exterior of said housing and being located at one side of said cavity; means attached to said movable member for electrically connecting said first and second electrical means; and means for connecting said first and second electrical means into an electrical circuit, said means being electrically connected to said first and second electrical means and projecting to the exterior of said housing.

The details of the invention are best explained directly by reference to the accompanying drawings. In Figs. 1 throughS of the drawings there is shown an adjustable potentiometer 10 of the invention which includes a base 12 and a cover 14 positioned upon this base. It is to be noted that'both the base 12 and the cover 14 are of roughly the same exterior shape as a small square wafer and that the exterior dimensions of the cover 14 are smaller than the exterior dimensions of the base 12 so that part of the upper surface 16 of the base 12 is exposed when the cover is located on it. The base 12 and the cover 14 are preferably formed out of a non-conductive material such as, for example, a suitable phenolic material or a dielectric ceramic. These two members are put together by suitable conventional means such as, for example, an adhesive, so as to define an internal cavity 18 of disc like shape between them.

'I'he upper surface 16 of the base 12 is of flat configuration and includes an arcuate resistance strip 20. formed out of appropriate conventional material such as, for example, a resistance ink. The ends of this resistance strip are overlaid by parts of terminals 22 and 24. These terminals are preferably formed of a silver ink or the like and extend from the resistance strip 20 to adjacent edges 26 of the base 12 so that they may be readily connected to various wires or other means used to electrically connect the potentiometer 10 into a circuit. Within the center of the arcuate resistance strip 20 there is located upon the upper surface 16 a circular end 28 of a terminal 30 an electrical return which is similar to the terminals 22 and 24 and which projects'to adjacent edge 26 of the base 12.

Disposed along. the edges 26of'the base 12 and edges 32 of the cover 14 are a series of grooves 34 which are specifically designed to hold the various wires such as, for example, wires employed in the so-called Tinker Toy type of construction when the potentiometer 10 is mounted in this type of an assembly. With this construction the various terminals 22, 24, and 30 may be secured directly to these wires by solder orother like means as desired so that as a double headed screw 36-disposed within a slot 38 within the cover 14 is turned a disc 40 located within the cavity 18 is turned, placing'resilient contacts 42 and 44 in engagement with different portions of the resistance strip 20 and with the same portion of the circular end 28 at the terminal 34. This construction is best understood with reference to Figs. 3 and 4 of the drawings.

The screw 36 is provided with grooves 46 which are designed to be engaged by projections 48 formed upon the cover 14 within the slot 38 so as to hold this screw in position with the threads 50 on it projecting a short distance through an opening 52 in the cover 14 connecting the slot 38 and the cavity 18. Thus, with this construction the threads 50 are located within the cover 14 so as to engage with what are in effect gear teeth 54 formed on the periphery of the disc 40.' The contacts 42 and 44 are formed out of the disc 40 by a simple punching operation so as to include ends 56 and 58, respectively, which are designed to engage the resistance strip 20 and the circular end 28'. The disc 40 is preferably formed out of a comparatively strong resilient metal such as, for example, brass, by a simple metal stamping operation, and is of such a dimension as to fit closely within the cavity 18. The contact 44 normally holds this disc 40 in a desired position within the cavity 18 parallel to the surface 16. The screw 36 is preferably formed out of such non-conductive materials as nylon or the like, and is located at the side of the cavity 18.

In Fig. of the drawings a modified potentiometer 60 of the invention is shown which difiers from the potentiometer solely in that the disc 40 previously described is replaced by a ring 62 having gear teeth 64' such as the teeth 54 formed on the outer periphery thereof. Within this ring is held a resilient metal contact ring 66 of partially circular shape having formed thereon resilient contact arms 68 and 70 engaging the resistance strip 20' and the circular end 28. With this construction the contact ring 66 is preferably larger than 180 of a circle so that it may be easily held in position within the ring 62 by spring tension. If desired, the contact ring 66 may be secured to the ring 62 by the use of rivets or an adhesive. The ring 62 may be formed either out of metal or of a non-conductive material such as, for example, phenolic resin. In the latter preferred case it is possible to form the screw 36 shown in this figure out of metal.

Those skilled in the art will realize that all of the parts of the potentiometer 60 which are the same as the various parts of the potentiometer 10 previously de-- by the primes of the same numerals used earlier in this 7 description.

InFigs. 7, 8, and 9 of the drawings a second modified.

cludes a base 74, a spacer 76 and a cover 78'. All of these three members are preferably formed out of a nonconductive material such as, for example, a ceramic or a phenolic resin in such a manner that the edges 80 of the spacer 76 are shorter than the edges 82 of the base 74 and the cover 78. Appropriate grooves or notches 84, similar to the grooves 34 previously described, are pro vided in the edges 80 and 82 for the same purpose as the grooves 34. The base 74, spacer 76 and the cover 78 may be attached to one another in any convenient manner such as, for example, through the use of an adhesive or the use of rivets so as to form a composite sandwich-like construction as illustrated.

Within the spacer 76 there is located a circular opening 86 which in the sandwich-like construction serves to define together with the base 74 and the cover 78 a cavity 88 such as the cavity 18 previously described. On the top surface 90 of the base 74 there is provided a resistance strip 20' similar to the resistance strip 20 'as to be concentrically located with respect to this resistance strip.

Within the base 74 and the cover 78 there are located aligned cylindrical holes 94 which are designed to carry a pin 96 serving as a shaft, whereby a metal disc 98 attached to this pin by solder or the like may be rotated about this pin through the operation of a small gear 100.

The gear 100 is mounted similarly to the disc 98 about a.

pin 102 located within aligned holes (not shown) in the base 74 and the cover 78 so as to be held normallywithin an opening 106 in the spacer 76 so that the teeth formed upon the gear 100 can coact with gear teeth 108 formed on the periphery of the disc 98 and so that the gear 100 is at one side of the cavity 88. Contacts 110 and 112 are formed on the disc 98 in a similar manner to the manner in which the contacts 42 and 44 are formed on the disc 40 in order to engage the resistance strip 20' and the end 98 of the terminal 30 employed. The electrical conduction means employed on the base 74 are the same as those used in the potentiometer 60. 9

Those skilled in the art will realize both the modified potentiometers 60 and 72 can be connected to various wires in essentially the same manner as the potentiometer 10. All of these three different constructions are quite advantageous inasmuch as with them quite fine adjustment is possible through the use of what amounts to gear reduction means formed on the discs 40, 40', and 98 and on the screws 36, 36 and on the gear 100. These constructions are quite advantageous for assembly in complex electrical assemblies such as those of the so-called Tinker Toy project inasmuch as the means used to adjust them are relatively small and are located in such a manner as to not to interfere to any material extent with the com-- plete assembly. Further, all of the potentiometers, 10, 60 and 72 are very thin, small devices which are quite reliable in use and which can be quite easily constructedtions of this category are considered to be part of the" present invention insofar as they are defined in the appended claim.

I claim: A new and improved potentiometer which includes: a

pen-conductive base; a terminal serving as an electrical return mounted on said base, said terminal including a circular end centrally positioned upon said base; an arcuate electrical resistance strip mounted on said base concentric with said circular end; electrical terminals positioned upon said base, said electrical terminals being in electrical communication with the ends of said arcuate resistance strip; a cover positioned over said base, said cover including an opening formed therein so as to define an internal cavity of disc-like shape between said cover and said base; a resilient metal disc positioned within said cavity; means defining electrical contacts engaging said arcuate resistance strip and said circular end formed on said disc; gear teeth formed on the periphery of said disc; means defining a 6 slot within said cover; a screw located within said slot, the threads of said screw engaging said gear teeth on said disc whereby as said screw is turned, said disc is rotated within said cavity.

References Cited in the file of this patent UNITED STATES PATENTS 586,864 Pieper July 20, 1897 10 2,197,312 Nelson Apr. 16, 1940 2,451,241 Rosentretcr Oct. 12, 1948 2,541,682 Tellkamp July 11, 1950 

